CODEWITHSUNDEEP
javarestmime-types
arthur
arthur

Reputation: 3325

Rest | MIME types : acceptance order

for class exposing resource "/hello":

@Path("/hello")
public class Test {


    //-- produces MIME type text/plain
    @GET
    @Produces(MediaType.TEXT_PLAIN)
    public  String thankYouTxt(){
        System.out.println("thankYouTxt");

        return "thankYouTxt\n";
    }

    //-- consumes MIME type text/plain
    @GET
    @Consumes(MediaType.TEXT_PLAIN)
    public String thankYouInputTxt(){
        System.out.println("thankYouInputTxt");
        return "thankYouInputTxt";

    }


    //-- produces MIME type text/html
    @GET
    @Produces(MediaType.TEXT_HTML)
    public  String thankYouHTML(){
        System.out.println("thankYouHTML"); 
        return "thankYouTxtHTML";
    }


    //-- consumes MIME type text/html
    @GET
    @Consumes(MediaType.TEXT_HTML)
    public  void thankYouInputHTML(){
        System.out.println("thankYouInputHTML");
        //return "thankYouInputHTML";
    }



    //-- produces MIME type text/xml 
    @GET
    @Produces(MediaType.TEXT_XML)
    public  String thankYouXML(){
        System.out.println("thankYouXml");
        return "<?xml version=\"1.0\"?> <message>thankYouTxt</message>";
    }
    //-- consumes MIME type text/xml    
    @GET
    @Consumes(MediaType.TEXT_XML)
    public String thankYouInputXML(){
        System.out.println("thankYouInputXML");
        return "thankYouInputXML";
    }



}

on the Api docu they state about the MIME acceptance order:

If a resource class is capable of producing more that one MIME media type, the resource method chosen will correspond to the most acceptable media type as declared by the client. More specifically, the Accept header of the HTTP request declared what is most acceptable. For example if the Accept header is Accept: text/plain, the doGetAsPlainText method will be invoked. Alternatively if the Accept header is Accept: text/plain;q=0.9, text/html, which declares that the client can accept media types of text/plain and text/html, but prefers the latter, then the doGetAsHtml method will be invoked.

who/what decides which MIME type (text/html) to consume rather than another one (text/html) ?

Upvotes: 0

Views: 910

Answers (1)

fge
fge

Reputation: 121860

OK, rephrasing the documentation since there seems to be a misunderstanding:

the resource method chosen will correspond to the most acceptable media type as declared by the client

and then:

the Accept header of the HTTP request declare[s] what is most acceptable

This header has the following form:

Accept: media/type1[;q=pref], media/type2[;q=pref], etc etc

When q is not mentioned it is 1.0.

If you have a request with methods producing, say, foo/bar and tar/feathers, if the accept header declares an acceptance of 1 for the first but 0 for the second then the method producing foo/bar will run. If, on the other hand the first has acceptance 0.5 but the second has acceptance 0.6, then... You get the picture.

As to what happens if no type is really preferred, the doc does not even say. But then the client should decide itself in the first place.

Upvotes: 1

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